This is my first post here on this forum. Our 3790RD arrives in about a week!
Try the Hidden Hitch 82201. I've run one on my old Wildcat 31QBH for that past 12.5 years towing jetskis and hanging bike rack. It bolts on. I welded some 2x3 along the frame so the bolts could be installed in the tube rather than on the bottom flange of the frame beam.
You do need to verify the frame width on the trailer to make sure it fits. I can get you the installed dimension until Tuesday when the trailer goes to another home.
https://www.amazon.com/Draw-Tite-822.../dp/B0075HNG0C